An increasing amount of data, in the form of electronic mail, websites, documents, databases, and data files, is used by and accessible to a user. A search system is important for finding desired information from the large amount of data available.
Conventionally, various search systems exist. However each search system has its own limitations. A particular search system may be inaccurate, inefficient, or incapable of performing a particular search on a particular type of data.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.